This T32 Training Grant has for more than three decades focused on the successful training of research-oriented pathologist-scientists and other basic scientists in the MGH Pathology department. Over the past two five-year funding periods, trainees have published a considerable number of papers, including many in high quality journals, and have competed successfully faculty positions in prestigious universities and medical schools and for research-focused positions in industry. The mentors of this current proposal comprise 29 Harvard and Massachusetts Institute of Technology faculty who are primarily centered in the Massachusetts General Hospital Pathology department and Cancer Center. This interactive, overlapping community of scientists and physician- scientists is organized into thematic programs that include: cancer genetics; cancer epigenetics; animal models of cancer; RNA biology; tissue, cell, and genome engineering technologies; cell cycle control and DNA damage repair; stem cell biology; immunology and chemical biology; and in vivo imaging for cancer biology and diagnosis. As in previous cycles, the trainees will be selected from a highly competitive pool of MD, MD-PhD and PhD applicants on the basis of prior academic and research achievements and evidence of a strong commitment to a career in cancer biology. The period of training will be two or three years for each successful applicant. An active and program- specific recruitment and retention program to enhance diversity ensures that diverse applicants have access to, and will succeed in, the training program. In summary, the proposed T32 program renewal capitalizes on a highly interactive, experienced and focused faculty; a distinguished record of training productive physicians and scientists, including underrepresented minorities; state-of-the-art facilities and educational resources; and exposure of the trainees to basic and translational aspects of cancer biology.